Chairs designed for use particularly in office environments and the like are being increasingly provided with adjustment features so as to improve the ergonomics of the chair, particularly in those situations where the chair is used for long periods of time, such as when an occupant is working at a computer terminal, to provide improved comfort and healthful support of the occupant's body. One of the areas which has been addressed to improve such comfort relates to the chair arms, and some known chairs have provided arms having position adjustability, particularly with respect to the ability to vary the armrest height relative to the seat. The known chairs which possess height-adjustable chair arms typically employ vertically telescopic supports and a cooperating releasable latch arrangement for permitting height adjustment. Most known arrangements, however, have disadvantages, either from a manufacturing or structural viewpoint, or from an operational viewpoint. For example, many of the structures are undesirably complex, and/or the overall support arrangement and cooperating latch mechanism is such as to make release of the latch and adjustment of arm height difficult or inconvenient, particularly to an occupant seated in the chair.
Examples of known height-adjustable chair arms are shown in the following U.S. Pat. Nos. 5,439,267, 5,435,626, 5,393,125, 5,393,124, 5,388,892, 5,382,079, 5,368,365, 5,346,284, 5,324,096, 5,318,347 and 5,265,938.
Accordingly, it is an object of this invention to provide a chair having a height-adjustable arm assembly associated therewith, which arm assembly significantly improves upon and overcomes many of the disadvantages as briefly summarized above.
More specifically, the improved height-adjustable chair arm assembly of this invention provides an improved latching mechanism which extends through the arm rest and into the arm upright so as to permit easy and efficient unlatching and height adjustment if desired, with the occupant in a seated position being able to easily release and maintain the latching mechanism in an unlatched position while at the same time permitting the occupant to easily raise or lower the arm while seated, and then permit the latch to re-engage.
Briefly, the present invention comprises a chair having height-adjustable arm assemblies respectively mounted adjacent opposite sides of a seat. Each arm assembly includes a horizontally elongate armrest which is connected to an upper end of an arm upright. The arm upright includes a vertically oriented support segment which has a guide bore defined therein. The armrest includes a vertically elongate slide tube and a horizontally elongate arm element. The arm element is connected to an upper end of the slide tube. A lower end of the slide tube is movably mounted within the guide bore. A latch arrangement functions to permit the slide tube to be positioned relative to the support segment at any one of a plurality of height positions. The latch arrangement includes a cartridge assembly slidably received within a window defined in a vertical wall of the slide tube. The cartridge assembly includes a latch member which is movably supported within a box-like housing and is movable so as to engage one of a series of latching notches. A latch-activating mechanism functions to move the latch member between a latching position and a release position. The latch-activating mechanism includes an activating lever and an activating rod. The activating lever is pivotally supported on the arm element and the activating rod has an upper end which cooperates with the activating lever and a lower end that engages a roller which cooperates with a cam surface of the latch member.
Other objects and purposes of the invention will be apparent to persons familiar with structures of this general type upon reading the following specification and inspecting the accompanying drawings.